Diff Drop and Ford Performance CV Axles Install

[Dusty]

Hey guys we just uploaded our video on installing a Diff Drop kit from Broken Innovation along with a set of new CV axles from Ford Performance. If you're interested please check it out!



The Bronco's CV's are easily vulnerable to damage by over-extension, particularly in Broncos with suspension lifts. In other words, when your suspension flexes beyond the safe range intended by the Ford engineers, the CV joints can bind and damage the precision components of the joint, leading to anything from premature wear to catastrophic failure. Short of CV failure, over-extension can also tear the rubber dust boot which is an equally labor-intensive repair (though less expensive) that can lead to more severe CV joint damage if not addressed. Many suspension lifts allow the extent of down-travel to come dangerously close to the CV's safe operating limit. Heavier tire/wheel combos can exacerbate the situation as the added mass and inertia can "bounce" the components beyond their static limit, when cycling at speed under hard use. Add in other unauthorized mods like deleting the sway bar (which I've done, precisely to get more articulation) can also be a factor. So I've done quite a bit to my Bronco to put the CV's at a disadvantage. Lowering the differential a couple of inches helps even the playing field by relieving those operating angles at the extremity of travel.

We've had several CV joint and/or boot failures so we decided to address the issue once and for all by installing a diff drop. We chose the kit designed by forum member @TeocaliMG after following his thorough design process here on the forum. It's a well thought out design and as far as I can tell the only one you can get by itself (not part of some larger suspension kit). I swapped out the axles first, so if you're only interested in the Diff Drop install, skip ahead to 11:05 in the video.

While I was at it I did decide to start fresh with a brand new set of CV Axles from Ford Performance, since I had installed a pair of used axles when I swapped to the M210 FDU a few months back (see that video here). The rusty old used axles were of unknown integrity but I had already torn a CV boot on them, so I thought it was prudent to just pair the new Diff Drop with a brand new set of axles.

As I've become accustomed to doing with our install videos, I've just gone ahead and included the entire process, including mis-steps and learned lessons, so you can learn right along with me. I'm not a professional mechanic and I don't present myself as an expert, or my install videos as definitive bibles on how to do something. I try to include it all in there because something I cut out might have been useful to someone. But I do speed it up when appropriate, and try to weed out most of the idle time in order to keep things moving. For anyone who is just wondering what it takes to do installations like these I hope you find the format useful.

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[userdude]

Always with the great videos. Appreciate it!

 

[TeocaliMG]

Thanks for the shout out Dusty! I hope to do my axles (out of desire and not necessity hopefully) someday!

For those who may not know, regarding the diff drop, I did add a larger oversized washer like the OEM, as well as increase the diameter of the passenger side spacer to the kit, to better encapsulate the bushing, more like the OEM style.

I expected to have a terrible time getting those back bolts in, but for some reason it just worked for me. I must have gotten very lucky because I have heard from others its quite tricky. I used a floor jack under the diff kind of like you did, pretty sure I did not have the other mounts in, but I may have had them in loosely. Glad you got it in!

Edit: How are you liking the Recon Grapplers? Those are on my Radar as my next set of tires may step down from mud terrain to a more "generalist" all-terrain.

 

[Pilsner]

I am very not sold on diff drops. In the Tacoma world, they were shown over time to cause more damage than they saved when the diff is now more prone to damage as it sits lower. I'd much rather replace a CV than a diff. Not to mention that you lift to increase clearance and allow bigger tires, then drop the diff to give that clearance back. I'd rather replace a blown CV with something stronger like RCVs than drop the diff personally.

 

[TeocaliMG]

I am very not sold on diff drops. In the Tacoma world, they were shown over time to cause more damage than they saved when the diff is now more prone to damage as it sits lower. I'd much rather replace a CV than a diff. Not to mention that you lift to increase clearance and allow bigger tires, then drop the diff to give that clearance back. I'd rather replace a blown CV with something stronger like RCVs than drop the diff personally.

Ground clearance is a valid concern against diff drops, and certainly its easier and cheaper to fix a CV vs an axle, but I don't think axle replacements approach even 1/10th the number that CV replacements do. Unless the Taco world is using super weak housings (wouldnt be that surprised).

The likelihood of breaking a CV is orders of magnitude higher than the axle, especially when using lifts and bigger tires. And depending on the under shielding or housing material, you may not have to worry about the housing much at all. The rear diff for example is one of the most dragged-over-rocks components on the Bronco and people dont seem to have major problems with that (granted thats beefier).

Also, the way Toyotas are set up with the FDU (sourcing from tinkerers adventures videos) is set up very poorly for a diff drop. The way the front bracket is set up basically at the bottom of the diff to begin with really limits how you can design a diff drop without losing more ground clearance than you needed for the actual amount of drop.

 

[Dusty]

Thanks for the shout out Dusty! I hope to do my axles (out of desire and not necessity hopefully) someday!

For those who may not know, regarding the diff drop, I did add a larger oversized washer like the OEM, as well as increase the diameter of the passenger side spacer to the kit, to better encapsulate the bushing, more like the OEM style.

I expected to have a terrible time getting those back bolts in, but for some reason it just worked for me. I must have gotten very lucky because I have heard from others its quite tricky. I used a floor jack under the diff kind of like you did, pretty sure I did not have the other mounts in, but I may have had them in loosely. Glad you got it in!

Edit: How are you liking the Recon Grapplers? Those are on my Radar as my next set of tires may step down from mud terrain to a more "generalist" all-terrain.

Yeah I think those two top bolts are just something you have to fiddle with until they're in. It's like playing poker, sometimes you get a good hand on the first deal, sometimes it has to go around the table a few times before you get lucky.

I'm really liking the Recon Grapplers. I knew I wanted a more all-terrain style tire on my next set (my previous tires were Nitto Mud Grapplers) so I was looking at either these or the BFG KO3. I've always had great experiences with both BFG and Nitto. We do have a special relationship with Nitto at Icon so that's what I went with and they've been great. Very easy on the highway and they do great in rocks, sand, normal trails, etc.

 

[Dusty]

I am very not sold on diff drops. In the Tacoma world, they were shown over time to cause more damage than they saved when the diff is now more prone to damage as it sits lower. I'd much rather replace a CV than a diff. Not to mention that you lift to increase clearance and allow bigger tires, then drop the diff to give that clearance back. I'd rather replace a blown CV with something stronger like RCVs than drop the diff personally.

I can see your point but I really haven't lost much ground clearance, even after I fabricate a new bulge for my skid plate. Maybe an inch, and only in a very narrow ridge that is inline with my direction of travel. This is my first IFS 4X4 so I'm no stranger to having a big differential pumpkin hanging down right off the centerline of my front axle. This still has way more clearance under the front diff than my Early Bronco on 37's.

That said, I've always been one to try something out for myself rather than rely on the conventional wisdom of the internet. We'll see how it turns out with this one.

 

[Pilsner]

Ground clearance is a valid concern against diff drops, and certainly its easier and cheaper to fix a CV vs an axle, but I don't think axle replacements approach even 1/10th the number that CV replacements do. Unless the Taco world is using super weak housings (wouldnt be that surprised).

The likelihood of breaking a CV is orders of magnitude higher than the axle, especially when using lifts and bigger tires. And depending on the under shielding or housing material, you may not have to worry about the housing much at all. The rear diff for example is one of the most dragged-over-rocks components on the Bronco and people dont seem to have major problems with that (granted thats beefier).

Also, the way Toyotas are set up with the FDU (sourcing from tinkerers adventures videos) is set up very poorly for a diff drop. The way the front bracket is set up basically at the bottom of the diff to begin with really limits how you can design a diff drop without losing more ground clearance than you needed for the actual amount of drop.

The front diff in the 3rd gen Tacoma was aluminum (along with the m190) which is obviously not ideal. The M210 is cast. Both are significantly weaker than a solid D44 though and would not stand up to dragging or bouncing off a rock. I certainly wouldn't want the diff closer to stock skids, but 3/16 or 1/4 aftermarket skids would be a lot better. RCVs won't bind or break, however lockers in a IFS vehicle are always more risk than a SFA, so the good thing about keeping stock CVs is that they are likely a "fuse" in the front end, so I get both sides. I personally prefer the risk of repairing a CV shaft on trail than have a cracked housing. You can limp out with a blown CV, but the housing could render it stationary until you pull internals. I like to get pretty remote, so my concerns usually lend to what I can and cannot trail fix.

 

[TeocaliMG]

The front diff in the 3rd gen Tacoma was aluminum (along with the m190) which is obviously not ideal. The M210 is cast. Both are significantly weaker than a solid D44 though and would not stand up to dragging or bouncing off a rock. I certainly wouldn't want the diff closer to stock skids, but 3/16 or 1/4 aftermarket skids would be a lot better. RCVs won't bind or break, however lockers in a IFS vehicle are always more risk than a SFA, so the good thing about keeping stock CVs is that they are likely a "fuse" in the front end, so I get both sides. I personally prefer the risk of repairing a CV shaft on trail than have a cracked housing. You can limp out with a blown CV, but the housing could render it stationary until you pull internals. I like to get pretty remote, so my concerns usually lend to what I can and cannot trail fix.

Thats all fair. I have bounced/dragged my cast m210 housing multiple times without issue. Many others have too, the stock skid is open under the diff afterall.

The unused bolt hole on the bottom of my housing is oval now instead of round lol, but there are no leaks! It has been proven to be pretty stout (at least the M210). But to each their own.

 

[Pilsner]

I can see your point but I really haven't lost much ground clearance, even after I fabricate a new bulge for my skid plate. Maybe an inch, and only in a very narrow ridge that is inline with my direction of travel. This is my first IFS 4X4 so I'm no stranger to having a big differential pumpkin hanging down right off the centerline of my front axle. This still has way more clearance under the front diff than my Early Bronco on 37's.

That said, I've always been one to try something out for myself rather than rely on the conventional wisdom of the internet. We'll see how it turns out with this one.

Hey, I'd pay money for an extra inch! If you have skids, I doubt it will be an issue. Just something to consider.

 

[SnowBronco]

Yeah I think those two top bolts are just something you have to fiddle with until they're in. It's like playing poker, sometimes you get a good hand on the first deal, sometimes it has to go around the table a few times before you get lucky.

Yeah those rear bolts... I almost wanted to get my ten year old and his little hands & forearms to squeeze in there past the cats and shaft to feed em in... I got them just as my forearms started to cramp up lol. So that was good haha

I did not cut the bolt flange off the front skid.... Where it used to bolt to the bottom of the diff mount... I kinda want to drill out a hole and tap it for a new mount in @TeocaliMG drop mount to bolt the front skid directly to it... It does indeed line up!!

 

[murphtron]

Yeah those rear bolts... I almost wanted to get my ten year old and his little hands & forearms to squeeze in there past the cats and shaft to feed em in... I got them just as my forearms started to cramp up lol. So that was good haha

I did not cut the bolt flange off the front skid.... Where it used to bolt to the bottom of the diff mount... I kinda want to drill out a hole and tap it for a new mount in @TeocaliMG drop mount to bolt the front skid directly to it... It does indeed line up!!

Cool! Are you able to post a pic of this setup?

 

[SnowBronco]

Cool! Are you able to post a pic of this setup?

 

[murphtron]

That’s nice. I haven’t installed yet. Waiting to move to 35s. But I was curious about how you described mounting the skid to the new diff bracket. Assuming I understood you correctly.

 

[SnowBronco]

That’s nice. I haven’t installed yet. Waiting to move to 35s. But I was curious about how you described mounting the skid to the new diff bracket. Assuming I understood you correctly.

Yeah I figured that's probably what you meant after I replied ... But I do not have pics or vids of that just yet. I'll try to get some in the morning.

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